Specifications

3
Chapter
14
Configuring a Redundant Disk Array
ThischapterexplainstheRTM’ssupportforRAID(redundantarrayofinexpensivedisks)and
howtoconfigureaRAIDfromtheavailableharddiskdrives.Harddiskdrivearrayscanbe
configuredintheSASBIOS,whichistheBIOSfortheSAS/SATAcontroller.Someharddisk
drivesmustbeconnectedtotheRTMwithcablesbeforeyoucanincludetheminanarray.
Supported RAID configurations
TheRTM’sSAS/SATAcontrollersupportstheseRAIDlevelsandconfigurations:
• RAID1integratedmirroring(IM),whichprovidesredundancy.Twoharddiskdrives(a
primaryandsecondary)mustbeidentifiedtobeusedasexactcopies.Uptotwohotspare
harddiskdrivescanbeincludedincaseoneofthecopiedharddiskdrivesfails.Incaseof
failure,thecontentsoftheremaininggoodharddiskdrivecanbecopiedtoahotspare,
whichalsogetsacopyofallnewdata.Theavailableharddiskdrivecapacityisthesameas
thesmallestharddiskdriveorspareinthearray.
• RAID1integratedmirroringenhanced(IME),whichprovidesstripingandonecopyof
eachstripeforredundancy.Atleast3harddiskdrivesmustbeused,withamaximumof8
copies.Uptotwohotspareharddiskdrivescanbeincludedincaseoneofthe
participatingharddiskdrivesfails.Theavailableharddiskdrivecapacityisthesmallest
diskcapacityinthearraymultipliedbythenumberofharddiskdrivesinthearray,and
thendividedbytwo.ThisisduetothemirroredstripesusedintheIMEarra y.
• RAID0integratedstriping(IS),whichimprovesperformance.Atleast3harddiskdrives
mustbeidentifiedtoparticipate,withamaximumof10harddiskdrives.Theavailable
harddiskdrivecapacityisthecapacityofthesmallestharddiskdriveinthe array
multipliedbythenumberofharddiskdrivesinthearray.
TheSAS/SATAcontrollersupportsmultiplearraysatonce,includingarraysofdifferenttypes,
aslongasthenumberofavailableharddiskdrivesissufficienttosupportthearrays.For
additionalinformationonthesupportedRAIDoptions,seethe
IntegratedRAIDforSASUser’s
GuidefromLSILogicCorporation.